Investigating aerodynamics of a 3D blade in rainy conditions: Application of hybrid superhydrophobic-hydrophilic surfaces

Abstract

In the realm of wind turbine blade design, it is essential to consider the impacts of real-world environmental conditions. Among these, rain stands out as an unpredictable natural phenomenon, with its intensity varying based on environmental factors. This study delves into the aerodynamic effects of different rain intensities on a three-dimensional wind turbine blade—a crucial investigation since rain can influence both the efficiency of energy capture and operational safety. A custom OpenFoam solver was employed for numerical analysis, and its accuracy was first verified by contrasting simulation outcomes with experimental results. Our findings reveal that while the critical angle of attack is 14° in dry conditions, it increases to 17° under the influence of rain. When maintaining a constant angle of attack, rainy conditions result in a lowered lift coefficient and a heightened drag coefficient. Significantly, the thickness of the boundary layer and the presence of a separation bubble are deeply affected by rain intensity. During heavy rainfall, the boundary layer's thickness can diminish by up to six times compared to dry scenarios. Towards the study's conclusion, blades were integrated with hybrid superhydrophobic-hydrophilic surfaces to enhance aerodynamics during rainfall. Data suggests that these surface alterations effectively regulate the boundary layer's thickness and manage the flow separation zone, ultimately boosting the blade's aerodynamic efficiency in wet conditions. These findings set the stage for subsequent research focused on developing blade designs responsive to the ever-fluctuating environmental dynamics.